In most places, you can see only one of the pair of insulator manholes, just as you can usually see only the conduit and the rail closer to the center of the street. I think they may have scraped the street down a little more near the center mall curb.
Here are two places where the pair of manholes are at least partially exposed, photographed on different days under very different lighting conditions. In the lower photo, you can see where the conduit has been broken off by some later streetwork that is not at all evident now.